The disclosed subject matter relates generally to fittings and seals, and more specifically to fittings and seals with one or more feed-through sections.
Wire, cable, and tubing feed through fittings are used in various applications, including but not limited to engine, commercial, manufacturing, and industrial applications. Often one or more wires, cables, or tubes need to be fed through a wall, housing, baffle, etc., which separates different environments.
A feed-through typically performs one or more functions. It can act as a hermetic seal that prevents leakage of gas or fluids through the wall. It can cushion and protect wires, cables, and/or tubes from chaffing and cutting damage. It can provide strain relief. However, the CTE (Coefficient of Thermal Expansion) of flexible sealant materials (primarily polymers) is universally much greater than the CTE of metal or composite materials used to construct feed-through fitting bodies. This difference can result in the sealant pulling away from the wall of the bore in the fitting body during or after repeated thermal excursions, allowing unintended ingress or egress from the vessel through the fitting body/bore.